WANG Yan-hua1,2,WANG Cheng-zhang1,GAO Yong-ge2,YAN Xue-bing1,SHI Ying-hua1,HE-Yun3 (1.Engineering College of Animal Husbandry and Veterinary Science of Henan Agricultural University,Zhengzhou 450002,China;2.Forage and Feed Station of Henan Province,Zhengzhou 450008,China;3.College of Animal Science of the Institute of Science and Technology,Xinxiang 453003,China)

REN Qing-ji1,WU Gao-lin2,3,REN Gou-hua3 (1.Grassland Work Station of the Gannan Tibetan Autonomous State of Gansu Province,Hezuo 747000,China;2.Northwest Sci-Tech University of Agriculture and Forestry State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resource,Yangling 712100,China;3.Key Laboratory of Arid and Grassland Ecology of Ministry of Education of Lanzhou University,Lanzhou 730000,China)